Asian Seas Research Articles

Impacts of Atmospheric Pressure on the Annual Maximum of Monthly Sea-Levels in the Northeast Asian Marginal Seas

Monthly mean sea-levels have annual maxima in August in the northeast Asian marginal seas (NEAMS). Based on satellite altimetry data, the rising rate of the August NEAMS sea-level (ANS, 4.2 mm∙yr−1) is greater than those of the NEAMS (3.6 mm∙yr−1) and global (3.4 mm∙yr−1) annual mean sea-levels. Thus, the interannual variations of ANS are classified as relatively high (period H) and low (period L) years and have been analysed because of the high risk of sea-level fluctuation to the coastal regions in August. In period H, there are large atmospheric pressure gradients between the high pressure zone in the Kuroshio Extension (KE) and the low pressure zone in the west of Taiwan (WT). In period L, the atmospheric pressure gradients are small between the above-mentioned zones. Large atmospheric pressure gradients induce strong west-northwestward wind stresses and more Ekman transport from the northwest Pacific Ocean into the NEAMS. The correlation coefficient between August NEAMS sea-level index (ANSI), which is the difference of atmospheric pressure anomalies between the KE and the WT, and the August NEAMS sea-level anomaly (ANSA) is 0.73. Although there is a significant correlation (coefficient: 0.64) between ANSA and the East Asian summer monsoon index (EASMI), ANSI might be more useful in estimating the variability of ANSA.

Impact of Climate Factors and Human Activities on Water Resources in the Aral Sea Basin

The Aral Sea in Central Asia plays an essential role in the socio-economic development of the region. During the last six decades, there has been remarkable changes observed in the water level and areal extent of the Aral Sea Basin; however, the causes behind these changes are unclear. This study quantifies the impacts of climatic and anthropogenic drivers on Aral Sea and the contributions made by these drivers to the variations observed in the Aral Sea Basin. The spatial and temporal seasonal variations in groundwater budget have been analyzed using the total water storage (TWS) of the basin from 2002 to 2015. The results from this study revealed significant increases in the the mean air temperature, precipitation, and potential evapotranspiration rate from 1960 to 2015 in the Aral Sea Basin. The TWS time-series shows a statistically significant declining trend of about 2 to 4 cm per year presented by the surface water storage. Based on the average monthly values of TWS, March 2005 presented the highest anomaly ~7.85 cm, while October 2008 showed the lowest anomaly ~8.22 cm between 2002 to 2015. The groundwater level indicates a small increasing trend of approximately 0.05 cm/year during the study period. Furthermore, the negative relationship between water level, climatic, and anthropogenic factors showed that these factors projected critical impact on the water level fluctuations within the Aral Sea Basin.

Scaling up Integrative Collaborative Governance towards Sustainable Coastal Development: Contributions of the Integrated Coastal Management System in the East Asian Seas Region

Scaling up Integrative Collaborative Governance towards Sustainable Coastal Development: Contributions of the Integrated Coastal Management System in the East Asian Seas Region

Temporal variation in daily temperature minima in coral reefs of Nanwan Bay, Southern Taiwan

Temporal variation in seawater temperature plays a crucial role in coral reef ecology. Nanwan Bay, Southern Taiwan is home to well-developed coral reefs, which frequently experience cold-water intrusions caused by internal wave-induced upwelling, that manifest in distinct daily temperature minima. These temperature minima and their associated sources were studied by recording in situ bottom temperatures and sea levels observed at depths of 5 and 30 m from May 2007 to September 2008. These data were then compared to the East Asian Seas Nowcast/Forecast System, and it was found that daily temperature minima presented large variations with magnitudes of 2–3 °C over periods from days to months. It was further demonstrated that the cold-water intrusions may have originated from depths of ~100 m and were strongly affected by westward propagating mesoscale eddies from the Pacific basin. An impinging warm anticyclonic eddy in July 2007 may have combined with the El Niño, resulting in temperatures surpassing 29 °C and degree heating days >4.0 °C-days at both depths, which were coincidental with a mass coral bleaching event. This eddy’s impact was additionally evident in high correlations between daily temperature minima and residual sea levels, suggesting that mesoscale eddies alter stratification, substantially influence temperature variation, and play important roles in understanding ecological processes on coral reefs.

A study on the departure port of the Sinan shipwreck—A perspective based on the Chinese ceramic cargo

The 14th century Sinan (or Shinan) Shipwreck, located in the southwestern marine area of the Korean peninsula, is one of the most significant ancient shipwrecks in the East Asian seas. Several hypotheses have been proposed about the port of departure, although insufficient archaeological research has been carried out on this matter. This paper makes a detailed comparison between the ceramics found on the Sinan shipwreck and the contemporaneous ceramics unearthed in Fuzhou, Hangzhou, and Ningbo in China, using three parameters: places of origin, proportion of products from different kilns, and similarity in ware types. We confirm that the most likely departure port of the ship was Ningbo (at that time called Qingyuan), from the perspective of its ceramic cargo. This inspires us to re-evaluate the importance of Ningbo to the maritime trade in the East Asian seas.

Sea surface temperature anomaly in the coastal waters of Vietnam related to ENSO phenomenon

The studies on the impact of the ENSO phenomenon on climate and environment change have shown that the Bien Dong (Southeast Asia Sea) is strongly influenced by this phenomenon. This paper focuses on analyzing sea surface temperature (SST) monthly data for 16 years (7/2002–12/2017) in the coastal waters of Vietnam from MODIS satellite images of National Aeronautics and Space Administration (US NASA). The analysis results showed a clear pattern of ENSO impacts on SST in the coastal waters of Vietnam. However, the intensity of the ENSO phenomenon affecting the three studied areas is very different, and in terms of trend, the intensity gradually increases to the north. The period of impact of ENSO on SST in the coastal waters of Vietnam is often about one month later than the ONI index and the influenced duration lasts about 6 to 9 months. In addition, in the La Niña years, the values of the SST anomaly reflect quite well in terms of the intensity of the La Niña phenomenon. However, in the El Niño years, the SST anomaly index is not generally proportional to the ONI index. Specifically, in the years when El Niño phenomenon was considered to be weak, the SST anomaly index of the coastal waters of Vietnam is much higher than in the years when El Niño phenomenon was considered to be moderate or very strong. The above results are contributing to improving the understanding of the impact of the vagaries of the climate on the coastal waters of Vietnam, supporting scientists and managers in making measures to prevent and efficiently avoid, limit and mitigate the damage caused by ENSO, and to have reasonable alternatives in the protection of biodiversity and environment in the coastal waters of Vietnam. It could be considered as a “small piece” of the overall picture of the impacts of the ENSO phenomenon on global climate change.

Global Trends of Sea Surface Gravity Wave, Wind, and Coastal Wave Setup

AbstractAssessing trends of sea surface wave, wind, and coastal wave setup is of considerable scientific and practical importance in view of recent and projected long-term sea level rise due to global warming. Here we analyze global significant wave height (SWH) and wind data from 1993 to 2015 and a wave model to (i) calculate wave age and explain the causal, or the lack thereof, relationship between wave and wind trends; and (ii) estimate trends of coastal wave setup and its contributions to secular trends of relative sea level at coastal locations around the world. We show in-phase, increasing SWH and wind trends in regions dominated by younger waves, and decreasing SWH trends where older waves dominate and are unrelated to the local wind trends. In the central North Pacific where wave age is transitional, in-phase decreasing wave and wind trends are found over the west-northwestern region, but wave and wind trends are insignificantly correlated in the south-southeastern region; here, a reversed, upward momentum flux from wave to wind is postulated. We show that coastal wave setup depends primarily on open-ocean SWH but only weakly on wind, varying approximately like SWH/(wind speed)1/5. The wave-setup trends are shown to be increasing along many coastlines where the local relative sea level trends are also increasing: the North and Irish Seas, Mediterranean Sea, East and South Asian seas, and eastern United States, exacerbating the potential for increased floods along these populated coastlines.

Estimation of marine dimethyl sulfide emissions from East Asian seas and their impact on natural direct radiative forcing

This study investigated the impacts of marine dimethyl sulfide (DMS) emitted from East Asian seas on natural direct radiative forcing (DRF) based on a numerical modeling approach. The high-resolution (4 km) DMS emissions (i.e., DMS flux) were estimated from sea surface DMS concentrations and transfer velocity in the air-sea interface using satellite observations and model-predicted data during the period 2014–2016. We inputted these emission data into an aerosol optical model and then estimated the natural DRF of sulfate aerosols derived from the DMS flux (i.e., DMS-derived sulfate) using a radiative transfer model. The total mean DMS flux in the study area during the study period was estimated to be approximately 0.73 μmol/m2/day, with a maximum of 3.4 μmol/m2/day (December 2014) and a minimum of 0.12 μmol/m2/day (March 2014). The total mean negative forcing at the top of the atmosphere (DRFTOA) due to the DMS-derived sulfate was approximately −1.3 W m−2 in the target area during the study period. The monthly maximum (−2.8 W m−2) and minimum DRFTOA (−0.82 W m−2) occurred in December and March 2014, respectively, with the highest and lowest forcing at the surface and in the atmosphere during the same months. In terms of spatial distributions over the entire study area, negative DRFTOA exhibited a maximum of up to −8.8 W m−2 in the coastal sea near Shanghai, China, and a minimum of −0.6 W m−2 in the offshore sea of the East Sea, Korea. These increases and decreases in the natural DRFs were strongly attributed to the DMS fluxes, which were affected mainly by sea surface wind and/or partially by DMS concentrations, and relative humidity conditions in the study region.

Epistemological fractures: The decline of western paradigms. Beyond the current epistemic hegemony?

ABSTRACTThousands of people are drowning in the Mediterranean and in the South Asia Seas. At the USA borders or elsewhere, at this time, hundreds are killed or pushed back against the principle of non-refoulement of the 1951 Geneva Convention. There is global warming and the devastation of our only planet, through the suicidal power we command in the Anthropocene. Meanwhile, the violence against women (in peace and war) persists. In order to overcome the current epistemological hegemony, we need new radical ideas about our sustainable world, at least about the global south(s), feminism and the Anthropocene. We need to think of a different choice of civilization, one that has not yet been tested, with less competition, less individualism and less national selfishness. Let’s insist upon the primacy of life as such over human life, over specism, in an alternative future where humans, and men at that, are not always in charge.

Steric Sea Level Variability in the East Asian Seas estimated from Ocean Reanalysis Intercomparison Project Data

In this study, steric height variability in the East Asian Seas (EAS) has been analyzed by using ocean reanalysis intercomparison project (ORA-IP) data. Results show that there are significant correlations between ocean reanalysis and satellite data except the phase of annual cycle and interannual signals of the Yellow Sea. Reanalysis ensemble derived from 15-different assimilation systems depicts higher correlation (0.706) than objective analysis ensemble (0.296) in the EAS. This correlation coefficient is also much higher than that of the global ocean (0.441). For the longterm variability of the thermosteric sea level during 1993-2010, a significant warming trend is found in the East/Japan Sea, while cooling trend is shown around the Kuroshio extension area. For the halosteric sea level, a dominant freshening trend is found in the EAS. However, below 300 m depth around this area, the signal-to-noise ratio of the linear trend is generally less than one, which is related to the low density of observation data.

Regional validation of the Coastal Altimetry Waveform Retracking Expert System (CAWRES) over the largest archipelago in Southeast Asian seas

ABSTRACT This paper presents the latest finding on the validation of the novel Coastal Altimetry Waveform Retracking Expert System (CAWRES) that was previously developed for optimizing the sea level anomaly (SLA) over coastal oceans. The work is meant for the continuation of our previous works that have been successfully tested at two coastal sites in Australia and the United States. To further examine the potential of CAWRES of being applied to coastal region elsewhere, we extend the works to the largest archipelago at the Southeast Asia regions where complicated coastal topographies are experienced. The Jason-2 altimetric waveforms have been reprocessed using CAWRES to retrieve the retracked SLAs. Results in this study indicate that over coastal oceans, CAWRES records much higher (>80%) percentage of data than the standard Maximum Likelihood Estimator-4 (MLE4), <20%) retracker. The SLAs minimum distance of CAWRES is found to be similar to those of the Ice-1 ranging from 0.6 to 9 km. Comparison with tide gauge indicates that in six out of nine cases, the correlation of CAWRES is superior to those of the other retrackers with correlation ranging from 0.48 to 0.90. However, the Root Mean Square Error (RMSE) indicates no significant difference among all retrackers. Based on the results, it can be concluded that the performance of CAWRES is nearly similar to those of the Ice-1 retracker, except that CAWRES has a better correlation with tide gauge data. This remarks the needs of embedding the Ice-1 retracker in the CAWRES system.

La collection de bryozoaires du Prof. Dr Ehrhard Voigt (1905–2004) conservée à l'Institut Senckenberg de Francfort - 2e partie - Cténostomates et Chéilostomates hormis les Ascophores

The bryozoan collection of Prof. Dr Ehrhard Voigt (1905-2004) at the Senckenberg Research Institute in Frankfurt am Main, Germany is a world-renowned collection of great scientific value. It is the world's largest collection of fossil bryozoans from the Upper Cretaceous and Paleocene and a unique archive documenting the evolution of this phylum of marine invertebrates during this time interval in the Boreal Chalk Sea that extended from the British Isles to the Aral Sea in Central Asia. The Voigt Collection contains over 300,000 specimens and was relocated to the Senckenberg Institute in 2005 according to the bequest of Ehrhard Voigt. As a result of a DFG-funded project, we present here a three-part type catalogue of the holotypes and neotypes of 256 bryozoan species in the Voigt Collection, of which this is Part 2. In total over the three parts, 247 species are re-illustrated but the name-bearing type specimens of 20 species are missing and no material could be found for 9 species. Two species, described as ctenostome bryozoans by Ehrhard Voigt, are questionable, while a further three 'ctenostome' species and one 'ctenostome' genus are considered as ichnotaxa.

La collection de bryozoaires du Prof. Dr Ehrhard Voigt (1905–2004) conservée à l'Institut Senckenberg de Francfort - 1ère partie - Introduction et Cyclostomes.

The bryozoan collection of Prof. Dr Ehrhard Voigt (1905-2004) at the Senckenberg Research Institute in Frankfurt am Main, Germany is a world-renowned collection of great scientific value. It is the world's largest collection of fossil bryozoans from the Upper Cretaceous and Paleocene and a unique archive documenting the evolution of this phylum of marine invertebrates during this time interval in the Boreal Chalk Sea that extended from the British Isles to the Aral Sea in Central Asia. The Voigt Collection contains over 300,000 specimens and was relocated to the Senckenberg Institute in 2005 according to the bequest of Ehrhard Voigt. As a result of a DFG-funded project, we present here a three-part type catalogue of the holotypes and neotypes of 256 bryozoan species in the Voigt Collection, of which this is Part 1. In total over the three parts, 247 species are re-illustrated but the name-bearing type specimens of 20 species are missing and no material could be found for 9 species. Two species, described as ctenostome bryozoans by Ehrhard Voigt, are questionable, while a further three 'ctenostome' species and one 'ctenostome' genus are considered as ichnotaxa.

Revisiting the predictors for the long‐range forecasting of southwest monsoon rainfall over South Asia with a focus on Pakistan

The predictors of the south Asian summer monsoon used in statistical long‐range forecasting by the Indian and Pakistan Meteorological Departments have, in recent decades, had their validity reassessed. The results of such studies, including this one, show that the relationships between numerous predictors and the monsoon rainfall have changed over time, and many predictors have lost or gained significance. Tropical Atlantic sea surface temperature (SST) has been identified as a robust new predictor, having been found to exhibit a significant correlation with monsoon rainfall in northern Pakistan as well as with Indian summer monsoon rainfall. Empirical orthogonal function (EOF) analysis is performed on the Pakistan monsoon rainfall data in order to identify the dominant coupled modes of variability, on interannual timescales, for the classification of two sub‐regions of Pakistan. Overall, few predictors showed significant correlations with the monsoon rainfall across Pakistan. However, with respect to rainfall over northern Pakistan, significant correlations were found for the tropical Atlantic SST anomaly, equatorial southeast Indian Ocean SST anomaly and quasi‐biennial oscillation anomaly. With respect to rainfall over southern Pakistan, warm water volume anomaly, North Asia sea level pressure tendency and Nino3.4 SST tendency showed significant correlations. Although the predictability of Pakistan summer monsoon rainfall is low, a simple multiple linear regression model has nevertheless been developed for its prediction. The model has shown good predictive skill for the primary monsoon region of Pakistan

Holocene ostracod assemblages from the Co To Islands, northeastern Vietnam

Abstract. In this study, we investigated ostracod assemblages from the Co To Islands in northeastern Vietnam. We identified 77 ostracod species belonging to 46 genera in nine surface sediment samples and recognized three biofacies (I, II, and III) based on Q-mode cluster analysis. The dominant species of biofacies I and II were Aurila hataii, Loxoconcha japonica, and Xestoleberis hanaii, which commonly occur in seaweed beds from southern China to Japan. This is the first report on the ostracod assemblage from the open-sea area in northeastern Vietnam. We clarified that the ostracod assemblages in the Gulf of Tongking, including northern Vietnam, have a strong biogeographical relationship with East Asia seas. A new species, Loxoconcha cotoensis sp. nov., was described herein from the Co To Islands (http://www.zoobank.org/NomenclaturalActs/41d3fb9f-ae17-4215-82c1-0874a8bf1a30, last access: 3 June 2019).

History of Yellow River and Yangtze River delivering sediment to the Yellow Sea since 3.5 Ma: Tectonic or climate forcing?

Reconstructing the Plio-Pleistocene sedimentary history of the Yellow Sea, is important for understanding the long-term influence of the Yellow River (Huanghe) and/or Yangtze River (Changjiang) on the Asian marginal seas and to further constrain any links between river development, regional paleoenvironmental change, tectonic deformation and/or global climate change. Here we present the first high-resolution clay mineral record combined with Sr-Nd isotopic compositions from a 300-m long sediment core recovered in the western South Yellow Sea. Our study suggests that large-scale transgression in the Yellow Sea occurred after ∼0.8 Ma, possibly related to tectonic subsidence of eastern China coast and the Min-Zhe Uplift. In contrast, the sedimentary environment of Bohai and Yellow Seas was mainly dominated by fluvial/lacustrine deposits at 3.5–0.8 Ma. Provenance analysis suggests a major change in sediment provenance from the Yangtze River to the Yellow River at ∼0.8 Ma, which corresponds to the timing of the final integration of the Yellow River in its present form. At the same time the major channels of the Yangtze River migrated from the South Yellow Sea to the modern Yangtze River delta due to the subsidence of east China coast. The consistence in timing of the provenance transition and large-scale regional marine transgression suggests that tectonic deformation, rather than climate change, is the first-order control on the evolution of the Yellow and Yangtze Rivers and sedimentary environmental change in the Bohai and Yellow Seas.

Adapting to climate change in the fishery industry case study: Phuoc Hai and Phuoc Tinh fishing villages of Ba Ria – Vung Tau province, Vietnam

Ba Ria – Vung Tau Province is part of the South Eastern key economic zone. This province is the gate to the Southeast Asia Sea of the South Eastern region. Ba Ria – Vung Tau has a coastal line of 350 kilometers and the estimated area of the continental shelf of 100,000 square kilometers. These geographical conditions have helped developed fishery and seafood processing industry. In the late ten years, many changes in climate and weather condition has had strong impact on the local life of those who live in the coastal area and mostly live on fishery. In order to adapt with those changes, people have actively seeked and opted for different measures which are applicable for their socioeconomic condition. Using descriptive statistics to analyze both primary and secondary data of two study areas, this paper discuss some solutions the communities have used to adapt to climate change. Then the authors propose some recommendations to assist the people in selecting solutions for climate change adaptation.

The role of scale within an Ecosystem Approach to fisheries management: Policy and practice in Southeast Asian seas

Primary considerations for adopting an ecosystem approach to fisheries management (EAFM) as a management approach will involve an expanded scope of fisheries management over conventional approaches; specifically, EAFM will involve a broader scale of management. Development of a sub-regional EAFM plan can complement local, national, and regional fisheries management priorities, as well as help to catalyze management action at multiple levels that may not otherwise occur. A sub-regional EAFM policy planning approach has been undertaken for the Sulu-Sulawesi Seascape (SSS), a sub-region of Southeast Asia. This sub-regional policy planning approach illustrates how “scaling up” EAFM can support relevant international, regional, and other sub-regional fisheries management plans and environmental initiatives, while “scaling down” EAF can support relevant national, provincial/state, and local fisheries management plans in Indonesia, Malaysia and the Philippines.

Transcultural Fights: Fortification in Southeast Asian Seas during the Eighteenth Century

Abstract Defensive architecture in Southeast Asian port cities during the eighteenth century is a topic never addressed from a transnational perspective. This paper aims to analyze it as a phenomenon of scientific transfer, considering fortifications as a remarkable example of “open air science.” First, it shows the complex situation among antagonistic powers in the Malay and South China seas. From here, it aims to identify the connections between Dutch and Spanish proposals in the area. One model focused on protecting sea routes, while the other was more concerned about maintaining territorial integrity. Later, it considers how local kingdoms from China or Siam to the southern sultanates addressed the problem. Here, a variety of answers have been found, ranging from a complete rejection of European solutions to qualified adaptations and wholesale adoption of them. From all these examples, it is possible to evaluate the nature of technical transfer in a transnational perspective.

Paleogene evolution and demise of the proto‐Paratethys Sea in Central Asia (Tarim and Tajik basins): Role of intensified tectonic activity at ca. 41 Ma

AbstractThe proto‐Paratethys Sea covered a vast area extending from the Mediterranean Tethys to the Tarim Basin in western China during Cretaceous and early Paleogene. Climate modelling and proxy studies suggest that Asian aridification has been governed by westerly moisture modulated by fluctuations of the proto‐Paratethys Sea. Transgressive and regressive episodes of the proto‐Paratethys Sea have been previously recognized but their timing, extent and depositional environments remain poorly constrained. This hampers understanding of their driving mechanisms (tectonic and/or eustatic) and their contribution to Asian aridification. Here, we present a new chronostratigraphic framework based on biostratigraphy and magnetostratigraphy as well as a detailed palaeoenvironmental analysis for the Paleogene proto‐Paratethys Sea incursions in the Tajik and Tarim basins. This enables us to identify the major drivers of marine fluctuations and their potential consequences on Asian aridification. A major regional restriction event, marked by the exceptionally thick (≤ 400 m) shelf evaporites is assigned a Danian‐Selandian age (ca. 63–59 Ma) in the Aertashi Formation. This is followed by the largest recorded proto‐Paratethys Sea incursion with a transgression estimated as early Thanetian (ca. 59–57 Ma) and a regression within the Ypresian (ca. 53–52 Ma), both within the Qimugen Formation. The transgression of the next incursion in the Kalatar and Wulagen formations is now constrained as early Lutetian (ca. 47–46 Ma), whereas its regression in the Bashibulake Formation is constrained as late Lutetian (ca. 41 Ma) and is associated with a drastic increase in both tectonic subsidence and basin infilling. The age of the final and least pronounced sea incursion restricted to the westernmost margin of the Tarim Basin is assigned as Bartonian–Priabonian (ca. 39.7–36.7 Ma). We interpret the long‐term westward retreat of the proto‐Paratethys Sea starting at ca. 41 Ma to be associated with far‐field tectonic effects of the Indo‐Asia collision and Pamir/Tibetan plateau uplift. Short‐term eustatic sea level transgressions are superimposed on this long‐term regression and seem coeval with the transgression events in the other northern Peri‐Tethyan sedimentary provinces for the 1st and 2nd sea incursions. However, the 3rd sea incursion is interpreted as related to tectonism. The transgressive and regressive intervals of the proto‐Paratethys Sea correlate well with the reported humid and arid phases, respectively in the Qaidam and Xining basins, thus demonstrating the role of the proto‐Paratethys Sea as an important moisture source for the Asian interior and its regression as a contributor to Asian aridification.